5 Ways to Minimize Generator Noise

In a survival scenario, few pieces of machinery are more valuable than a quality generator. At a time when we have become almost entirely dependent on electricity for survival, having the ability to generate power when the grid is down could be the difference between life and death.

However, generators are also known for being quite noisy, and there are several reasons this could be a problem, from minor issues such as irritating your neighbors to major issues such as attracting unwanted attention from roaming thieves. Thankfully, there are a few great ways to make your generator less noisy.

1. Build a Sound Wall Around the Generator

Building a wall around your generator is one of the quickest ways to drastically reduce its noise output. To build a sound wall, all you need to do is stack up cinder blocks around the generator. Stack the blocks one foot higher than the height of the generator, and leave a space of about six inches between the generator and the wall.

2. Reduce Vibration in the Engine Housing

A lot of the noise that a generator produces comes from vibration. To reduce that noise, you can add vibration dampening material to the engine housing. Look at the engine on your generator and notice the screws that secure the engine to the frame. Chances are there will already be rubber washers between the screws and the frame.

However, you can add a second rubber washer for even more noise reduction. You may have to replace the bolts with longer bolts in order to make room for a second washer, but the noise reduction is well worth the extra effort.

3. Add a Muffler

In the same way that a quality muffler can reduce the noise output of a vehicle, adding a muffler to your generator can help reduce its noise output as well. For most generators, a motorcycle muffler will work best, though you may need to create a custom pipe system in order to attach it.

4. Add Padding Beneath the Generator

Decide where you want to place your generator, then lay down some rubber waffle padding. This padding will help reduce vibration between the generator and whatever surface it is resting on, making for a quick and affordable way to reduce your generator noise.

5. Purchase a Quiet Generator

As technology advances, manufacturers are working to make generators more and more and quiet, and already there are some great options available that produce much less noise than the typical generator. These generators include:

• Champion Power Equipment 3,100W -This powerful generator is able to produce an impressive 3,100 Watts of power while still only having a decibel level of 58 dBA at 23 feet. Given that an average human conversation is 60 dBA, you can’t get much quieter than that, especially given the generator’s power.

The Champion Power Equipment 3,100W weighs less than 100 pounds, runs off a single cylinder 171cc 4-stroke OHV engine, and will run for 8 hours on a single tank of gasoline at 25% usage.

• Honda EU2000i 2,000W – At 2,000 W, the Honda EU2000i is a little less powerful than the Champion Power Equipment 3,100W, but it’s even quieter still. This generator is 59 dBA when it’s running at full power and you are standing right next to it. It also weighs about half as much as the Champion Power Equipment 3,100W, making it incredibly portable.

Though you may need more power than the Honda EU2000i offers, it is an excellent option to consider if maximum power isn’t a priority.

• Yamaha EF2000iS 2,000W – The Yamaha EF2000iS 2,000W is a little noisier than the Honda EU2000i if you are running it at full power, with a rating of 61 dBA. However, where this generator really shines is when you are running it at 25% power. At this level, the Yamaha EF2000iS 2,000W has a rating of just 51.5 dBA – which is almost whisper-quiet.

In most every other way, the Yamaha EF2000iS 2,000W is very comparable to the Honda, being roughly the same size and delivering the same power.

• Briggs & Stratton P3000 3,000W – Another more powerful option comparable to the Champion Power Equipment 3,100W, this 3,000W generator is able to deliver an impressive amount of power while being rated at 59 dBA. The high power output is great for backing up your home, and 1.5 gallons of gasoline will last you about 10 hours if you are running the generator at 25% power.

It’s worth noting that none of these generators don’t deliver quite the same level of power as a full-sized emergency generator. However, if noise reduction is a priority, then purchasing a quiet generator is an excellent option to consider.

In addition to being less noisy, these generators are also more portable and more fuel-efficient – both of which could prove to be quite advantageous in the right circumstances.

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Comments

Why hasn’t anyone mentioned solar generators? Yes they are more expensive but there’s no noise and if you have a large south facing window or glass door, you could have it inside, in theory. At least it would be safe to experiment with having it inside

1) Sounds travel further, and hold their volume, if directed with the wind.

2) A person in or near a noise generating area cannot hear more distant noises very well.

3) A person that is away from a noise generating area can often hear talking and other sounds beside the actual noise as well as, and in some cases even better than they can when the other person is not near a noise source. Has something to do with the human sounds ‘riding’ the noise sounds.

4) Single sounds can be very difficult to locate. Multiple sounds can be located fairly quickly, but it does take a bit of head turning (or microphone direction changes). So if a person can otherwise silently move from one point to another, limiting any sound release to one at each point, it will be more difficult to be located. However, this only works for a few moves. The brain can process those sound signals and get the pattern of movement with only a few repetitions of the sound.

5) Muffling a cough with fabric can change the sound enough to make it harder to discern. Muffle, do not try to suppress the cough physically.

6) Sounds can be very directional. Remember megaphones? A vocal sound director can be made, rather like a combination of a hearing tube and a megaphone. A padded opening large enough to surround the mouth, at the end of a curving tube increasing is size slowly, to straight up. The sound will go upwards, with very little going outwards.

One of the things that works somewhat for me is to clench my teeth firmly, but not really hard, and spread my lips as much as I can. This turns the cough into more of a huff, which does not seem to be as loud, or travel as far as an unrestricted cough. This does get tiresome if I am coughing constantly.

Just my opinion.

I believe there are quite a few things that can be done to reduce not only the sound signature, but air consumption, exhaust, and cooling air signatures. Plus, I will probably add a few things to reduce the chances of discovery through other means, too.

1. Since the genset does need to be protected from the weather, and barring an adequate place in the shelter a moderate size enclosure or a small building makes perfect sense. However, I do think there are a couple of alternate ways to provide that protection, and begin the task of mitigating the genset’s give-aways.

2. If a shed is already in place, and has some space to build in a sound insulated air cooling and sound reduction room, that might be enough for some of the small, already fairly quiet gensets. Running the exhaust through the wall or roof, with large screened and baffled engine cooling and combustion air intakes and exhausts to make sure it is both safe, and does not overheat.

3. An alternative to an actual shed with an air cooling/sound reduction room section, would be closer to a doghouse than a shed in size, all-be-it a very large one. The doghouse needs to be on skids, and it can have a floor or not. If it does have a floor, have heavy cross members across the floor joists to spread the weight of the genset over as much space as possible. Even if it is not very heavy.

You will probably want to go ahead and mount the genset on skids, too. Even if it has its own. You want higher ones, (4″ x 4″ treated lumber), so you can add a spring mounted platform, even if the genset is spring mounted on its frame. You want maximum vibration reduction. Plus, if the oil must be changed by draining it from the bottom of the oil pan, it will be much easier to have space under it for an automotive oil collection container than cobbling something up that probably will not work nearly as well.

Since the genset will be on springs to cut down on ground vibrations, you will need to use flex joints on fuel lines, exhaust lines, and electrical connections. And, depending on how many of the other things I recommend you decide to do, you may need some flexible ductwork connections. Okay. Vibration handled.

3. Exhaust first. I very highly recommend you pick up a spare muffler or two. A third one if you want to make what I am about to suggest and keep the original in reserve. The original muffler type and style needs to be on the engine, since the engine has been tuned to run best with it, and the muffler has been tuned to quieten the sound a reasonable amount and let the engine run efficiently.

That does not mean, however, that you cannot do additional quieting with additional mufflers. One in particular will be discussed below. Whether a secondary muffler is added or not, discharge the exhaust gasses into a large area that is sound deadened and opened to the sky.

This works in a couple of ways. One, the more compact the exhaust stream is, the louder it will be when it is discharged into the open air. By letting the muffler exhaust into a good sized room, that sound will be reduced by the sound insulated walls. Also, since the air is moving much more slowly, and upward, to boot, the remaining sound, already at a lower volume, will be going straight up, not out horizontally, making it very much more difficult to hear from any distance except straight up.

In order to reduce the mechanical noise of the engine running, the fan blowing air, generator whine, and such, the cooling air flow around the genset needs to be handled much the same way. If the room is well insulated, just a screen between it and a separate chamber in the expansion room will work. And again, open to the sky to direct that sound up, rather than out.

If you make arrangements for adequate cooling air flow, you can make a simple shroud to go over the genset and use large HVAC ductwork to move the hot, noisy air to the second expansion room for a bit more efficiency.

All good things. Now, if you add an aftermarket, preferably a Super Trapp Quiet Muffler ( https://www.jackssmallengines.com/Products/Super-Trapp/Quiet-Mufflers ) or a home built muffler, such as a water muffler, after the original muffler located in the exhaust expansion room, you can greatly reduce the final sound level even more. And get away with a smaller exhaust expansion room. A few tutorials from the internet or books from the library will give you the information to buy or build a second stage muffler if you do not want to buy one.

While not quite a muffler, if you use a shroud around the genset and ductwork to the second expansion chamber, you can use some sound absorbing baffles inside to reduce the amount of sound traveling with the air. The ductwork will need to be a bit bigger to compensate for the flow losses, but that will not be much.

With these changes, rather than a room size insulated room open to the sky, you can make another doghouse size room at one side or the rear of the genset doghouse, or just combine it with the heat and sound insulated wall between the two rooms, as well as the outer walls. It would be a good idea to insulate the entire building the same way, to reduce the signatures from the genset itself, too. Run the dividing wall between the two expansion rooms up, too. It can run all the way up, or be stopped somewhere in the lower area of the chimney. Once the ‘airs’ get some distance away from the sources, it will not make much difference if they are mixed.

Even with the walls well insulated, you will still want to build an additional wall all the way around the building, a couple inches away from the outside of the inner wall, with this outside wall being what is finished to get the particular look wanted to match the house or other outbuildings. However, this wall will be as holy as the holiest monk that ever lived. It will be your screened air intake for the engine combustion air, as well as the cooling air. Use wide overhangs on the roof with soffit screens to provide additional means of air flow.

And not only can it provide a very low speed, high volume air intake system for the genset, it can be one of several supplying the shelter(s). Some sound baffled ductwork from the cavity the width of the room, with a right angle turn near the opposite wall, from both walls, of course, will lower the sounds going out the intakes. When the air is flowing not much will escape anyway, but it might be necessary to run the genset when the intakes are open.

Run 4” – 6” PVC pipe from a collection point midway up one of the cavities and lay a pipeline to the shelter air intake room. Same precautions I always suggest. A sump leading to an absorption pit, a cut off valve, blast valves if at all possible.

You can also run a second PVC pipe from the shelter to the doghouse, and up the inside of the “chimney’ as part of the air exhaust of the shelter.

Too add a bit of ‘cute’ camouflage to the system, and since the expansion room needs to be well more than head height anyway, you can slope the roof quite a bit, bringing it down to 12″ or so inside, again well insulated, and build it several feet into the air. Add a chimney cap to it to keep rain and pests out, and you have a luxury doghouse that does not only conceal and isolate a genset, but with good aforethought, planning, and building, several other things already mentioned can be accomplished.

Another pair of alternatives. If the cooling and combustion air intake and engine exhaust and engine cooling air ducts have tees in them, with closing valves, medium diameter culvert can be run from the doghouse to a couple of rock features, water feature or two, playground equipment, patio set up, and probably some other things that would work well to camouflage the open ends of the air pipes and air ducts.

Rock cribs, in the form of decorative yard features, can be carefully, and artfully, arranged to allow air flow either in or out. Rock gabions using woven or welded wire fence, or even chain link fence, can be used as either decorations, or as actual fence posts. With the rocks stacked with air gaps, the screened intake or exhaust pipes can collect air or allow exhaust to escape.

By using PVC, ABS (for exhaust), or steel pipe as parts of various structures or elements of the place, many different possibilities present themselves to allow clandestine pulling in and blowing out air.

Not to mention, the Gabions might be used to support yard lights. Or antenna poles. Or security system poles or risers. Or intercom boxes. Or be used as fighting positions (but only if provisions are made so they cannot be used by an aggressor to harm you)

Besides the rock features, water features, playground construction and equipment, and patio construction and features, there are many more things that can be used to camouflage air movement infrastructure. Certain kinds of fences. Some types of fence posts. Guttering (which should be on every building), the very walls and roofs themselves.

‘Decretive’ cupolas, functional attic roof wind turbines and functional gable end ventilation screens. ‘Abandoned’ power poles. Just think outside the box and push the envelope. Oh. Often times while creating air handling infrastructure, the means to locate communications antennas and run communications wire will present themselves, so go ahead and get those elements installed during the building, even if not to be used right away.

If nothing else, use some sound insulation board and simply build a ‘chimney’ around the genset, large enough to be able to access it, as tall as is practical. Directing the sound upwards will go a very long way to preventing its spread outward. If the genset is set up on a solid stand a foot or too off the ground, not only will it be easier to work on, start, and service, but it will help prevent sound escaping the narrow slots at the very bottom of the ‘chimney’ required for air flow for the genset.

There are quite a few more ways to accomplish what the OP is asking about, so if anyone needs more, just e-mail me.

A recommended adjunct to having an auxiliary power system, be it a generator, solar, wind, micro-hydro, or even just candles for lighting, light discipline should be part of the overall plan. If others know you have power, and they do not, it will eventually be a problem during any major disaster or other situation, even many minor ones.

So having a blackout curtain system, whether it is actual curtains or not, and a plan and procedures to avoid light getting out when going from and to lighted areas from un-lighted areas should be a part of the overall plan and installation. This could simply be always turning off the lights before leaving or entering the lighted area, to a light lock (like an air lock, only set up to prevent light escaping) entry/exit.

With a little research you’ll find that (depending on the model/size/fuel type) generator noise consists (mostly) of mechanical (spinning engine and armature) noise, compounded by vibration, with some exhaust noise thrown in. The exception here is if there is no muffler or just a cheap (can type) device. While the exhaust noise is the most readily identified part of the total noise package, I think you’ll find the lions share of generator noise remaining once the exhaust noise is reduced significantly will be the machine parts operating at (governor controlled) higher speeds. Beware of disturbing the exhaust pressure too much and raising the back pressure (screws up fuel intake and may cause operating problems). The lower pitch of the exhaust (vs. the high pitch of the mechanical noise) doesn’t travel nearly as far. That’s why you box the genny in (absorb and/or deflect mechanical noise) vs. just putting a high efficiency muffler on it and calling it a day. So it would make sense to place the generator on grass or loose dirt (vs a hard surface; unless well padded), and at the very least, lean plywood sheets at a downward angle (all 4 sides) deflecting the noise into the soft surface. I’d suspect a 50+/- 10% mechanical noise reduction just from that (speculating; not scientific). Set up behind your house, add some insulation to the plywood and reduce the (ears on the street) noise footprint even further. Worked well for me anyway…

I bought a Champion 3500W generator from Cabela’s. It’s duel powered- gasoline OR propane. It uses 1/2 lbs of propane per hour. With just four 40lb tanks, I can go for 2 weeks. (80 hrs per tank). Longer if I only run it for a couple hours on, a couple hours off…

Champion 3650 Watt Portable Generator costs only $299.95 and a noise level of only 64 Decibels. This article recommends a Champion 3,100 watt that costs $1,000 I guess because it is 60 decibels??? I would rather have more wattage and an hour more run time while 4 decibels is not a factor don’t you think!!! By the way I own the 3650 watt unit and it is very quite!!!1

I know where to get CEMENT/CONCRETE blocks, but I have no idea where to get cinder blocks!!

You can reduce the sound in your concrete block “cage” by using sound deadening material on the floor and on the walls. I would suggest that the walls we made higher than the one foot higher than suggested, go maybe 2-3 feet higher.

Back when I was in the military we had 2 meter long flex hoses on our generator exhaust. At the end was a small muffler. We would dig a small hole and cover the muffler with a shovel full of dry loose dirt for more sound suppression. It also helps to control exhaust fumes as you can relocate the muffler a little to keep wind from blowing the fumes into a shelter. My generator was stolen last winter. get a chain and lock.

This morning, after reading the comments complaining about the idea of bringing a generator into a laundry room and venting it through the laundry exhaust, I decided to remove that suggestion altogether. I know it can be done in theory if you’re very careful, make sure everything is sealed, and have a monoxide detector.

The problem is, there are too many scenarios where something could go wrong. Someone could fail to vent it properly, the monoxide detector could malfunction or the batteries could die, people would be forced to abandon their home even if the detector went off, etc. Considering that, I decided it’s just not worth the risk.

I appreciate the comments calling me out on this, I really don’t want to give bad advice. I remember reading this idea in a survival book a long time ago but I can’t remember where, and I really should have looked into it more before suggesting it.

I already had a (thankfully, very noisy) leak in exaust pipes. If you send gases to outer places and it leaks, you can have CO inside. My generator was outside and pipes conducting to reduce exaust temp/noise.

Recommending a generator be brought indoors, plumbed up by a non- professional homeowner following some mealy mouthed platitudes about safety is grossly negligent on your part. I hope you have a good attorney.

Well here is something I have started obtaining my parts and pieces for.
I don’t “think” I like the idea of venting through a dryer vent most go down and horizontal. I purchased a Y adapter for the venting from my furnace / water heater with a removable cap. I will run a duct down to the generator. I thought of just making an insulated box that can be screwed together easily with a vent for air intake. I do have a monoxide detector that I acquired.
I also spent a few bucks and purchased an adapter to run on natural gas, propane or gasoline. Remember the rule – 3 is 2, 2 is 1 and 1 is none. 🙂

Also, using cinder blocks or any other hard surface just redirects the sound. Think of those sound walls along the freeways or noisy restaurants. You need a material that absorbs the sound.

Sakes. Telling people to bring generators (or any running gas engine) indoors seems risky. Yes, you can vent the exhaust outside, but that’s a tricky operation. It ALL has to go outside — not just some of it. Leaving a window open in the garage, for instance, won’t be enough. Monoxide will concentrate anyhow. The vent also has to get the fumes far enough from the house or they’ll just sit out there and seep in some other cracks.

A battery-operated monoxide detector is a good grid-down bit of gear.

Building cinderblock walls really defeat the portability of generators, but yes, solid walls help deflect sound.

The exhaust sound is by far the loudest element. Work on the loudest thing first. I’m experimenting with additional mufflers and aiming the exhaust up. Quieter, but still not quiet.

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